The present invention relates to a power supply unit for extending a function of an apparatus detachably provided with a power supply.
In recent years, attendant on the reductions in size and weight of image pickup apparatuses represented by digital cameras, the batteries mounted in the image pickup apparatuses have come to be formed in rectangular parallelopiped shapes which are advantageous for reductions in size and weight. In the case of an image pickup apparatus to which a battery is applied, for preventing mis-insertion of the battery or breakage of the image pickup apparatus, it is desirable to form the image pickup apparatus by use of a member or members rigid enough to endure bending moments, which has been impeding the reductions in size and weight.
In view of the above, as shown in FIG. 25, the battery 14 described in Japanese Patent Laid-Open No. 2003-317689 is formed in a rectangular parallelopiped shape in which the length of the edges in the insertion direction is set greater than the length of the edges in the width direction for the purpose of preventing mis-insertion into the image pickup apparatus, and an armor 140 is provided with notches 141 at edges thereof, whereby the mis-insertion is prevented assuredly, and it is made easier to reduce the size and weight of the image pickup apparatus or the like to which the battery 14 is mounted. The armor 140 is provided with terminals 142 to be electrically connected to terminals of the image pickup apparatus into which the battery 14 is to be mounted. The number and the locations of the notches 141 are so determined that the end face 143 does not have a center of symmetry. On the other hand, a cell holder in the image pickup apparatus for storing the battery has an internal shape substantially the same as the external shape of the armor 140, and is provided with projected portions for engagement with the notches 141, 141 when the battery 14 is stored in the cell holder. Incidentally, batteries of the same type as the battery described in Japanese Patent Laid-Open No. 2003-317689 are described in Japanese Patent Laid-Open Nos. Hei 11-307072, 2001-76700, and Hei 11-3692.
In the case of extending a function of an apparatus detachably provided with a battery, as in the case of the image pickup apparatus described in Japanese Patent Laid-Open No. Hei 6-132021, for example, a functional variation is added in the thickness direction of the apparatus.